Method of and apparatus for producing alternating currents



Nov. 16,1926. 1,607,277

- P. c. HEWITT METHOD OF AND APPARATUS FOR PRODUCING ALTERNATING CURRENTS Filed Dec. 1, 1920 2 Sheets-Sheet l 29 l I 2 l g INVENTOR.

26s %TORNEY6' Nov, 16, 1926. 1,607,277

P. c, HEWITT METHOD OF AND APPARATUS FOR PRODUCING ALTERNATING. CURRE NTS Filed Dec. ,1920 2 sheets-sheet 2- y INVENTOR. v 1221/ WM 22 Y 1 IZ?AT?ORNEYJ Patented Nov. 16, 1926.

UNITED STATES.

PATENT OFFICE- PETER COOPER HEWITT, OF RINGWOOD MANOR, NEW JERSEY; THE FARMERS LOAN AND TRUST COMPANY, EXECUTOR OESAID PETER COOPER HEWITT, DECEASED, ASSIGNOR TO COOPER HEWITT ELECTRIC COIIPANY, OF HOBOKEN, NEW JERSEY, A

CORPORATION OF NEW JERSEY METHOD OF AND APPARA'LUS'I'OR PRODUCING ALTERNATING CURRENTS.

Application filed December 1, 1920. Serial No. 427,485.

alternating currents, currents of low and high frequencies and of large quantity currents as well as feeble currents, and particularly useful in the signaling art.

Further, my invention consists of novel form of gas or vapor or vacuum devices, by

which is meant a gap in a true conductor comprising the true conductorterminals and a the space between them, which space may consist of as near nothing as is obtainable or of a gas or vapor, or of a mixture of gases'or vapors in various degrees of density; that is, the terminals of a true conductor between which there is more or less gas or vapor whose amount may approach zero.

My invention further consists of the control of electric current before and while flowing in a circuit of the character describedabove.

It further consists in controlling the voltage required to pass current and required to maintain current flow in a device of the type above referred to.

It further consists in a circu'it'associated with the device to facilitate its operation, the whole providing a controlling means for, or. means-- for controlling, an electric circuit. f

It further consists in providing means for obtaining a suitable gas or vapor density between the conductor terminals and also inproviding means for the support of the.

proximity to the positive. terminal, where the solid material of the shield approximates ten per cent (10%) of the area occupied by theperforations and the material bounding them. For example, a perforate solid material having a depth equal to its width works well and it. is therefore possible to use wire gauze as a shield material. The action is increased bythe use'of a multiplicity of shields in parallel and electrically connected. In some instances it may be advantageous that they be connected with varying impedance in their respective circuits.

In the accompanying drawings and by way of an example I have illustrated in Fig. 1 a device and circuits. showing the general organization of a typical apparatus; Fig. 2 is an alternative form of tube for that shown in Fig. 1; and Fig. 3' is a device and circuits with a simple form of control circuit.

Referring to the drawings, Fig. 1, 1 is a tube of the general type referred to above and is shown and described in my application Ser. No. 397,965, filed July 21, 1920.. The tube 1 is provided with a positive electrode 2, of w1re gauze, or a carbon plate or other suitable material. An active negative terminal is conventionally shown at 3-4 of the mercury type. However, this active negative may be ofsolid material as shown at 3, Fig. 2, and consists of tun sten, tantalum,magnesi'a mixture or any su table solid material. In devices of this character it is necessary that the main negative terminal 3 or 3 be maintained in a conducting condition as by heating a portion of the terminal to incandescence which is accomplished by forming a hot spot on the surface of the terminal by passing current therethrough from a source and circuit conventionally indicated at-23 and 23 or by heating the terminals to incandescence by other means. The hot spot, above referred to, is accomplished by the lowest resistance for large currents.

Current-is applied to the tube 1 from a source-of direct current 11 through mains 8 and 9, the main switch. being shown at 10,

a switch shown at14 being provided for throwing in inductance 15,.or resistance 17, as the operator'may find necessary in operating the apparatus. An inductive coil In the space between the positive 2 and the negative 3, I -mount control shields 5 and 7 of the perforate material, such as wire gauze, of tungsten, molybdenum, or other suitable material, asset forth in my application above referred to, said shields serving as control terminals and functioning to prevent current concentration, thus aiding in the operation of the device. The circuit for the control shields 5 and 7, in this instance, comprises an inductive coil 20 in inductive relation to the coils 29 and 16 of the main circuit and the work circuit, a capacity 31 connected to main cathode 3 by a conductor 35 to the active negative 3 and also connected through a capacity 32 by a conductor 36 to a capacity 30, and by a conductor 37 to the other side of the coil 20. The shields 5 and 7 are connected across the terminals of the coil 20 by the leads 8 and 9, respectively. The shields 5 and 7 are maintained at proper potentials by the batteries 22 and 23 through the conductors 38 and 39 respectively. While the switch 14 in the main line from the source 11'is shown connected directly to said source, I may insert in the line an inductance 15 or resistance 17 to meet requirements of service. There is' always some capacity in the circuit which acts as capacity connected from the input lead to coil 29 and negative terminal 3 of the device. In case such capacity is insuificient, it may beincreased by a capacity bridged across the main circuit leading to the apparatus.

In operation, current is caused to flow to flow from shield 7; and battery 22 being connected through lead 38-, 37, 8, to shield 5 is so adjusted as to cause current to flow from shield 5; Under certain conditions of operation after such initial flow is established, the voltage of battery 22 may be diminished.

The closing of the switch 10 at the source 11 establishes current flow in the main circuit, whereupon current flows through coil 29, terminal 2, to terminal 3, conductor 9, back to source 11. The field established at coil 29 induces current flow in the control circuit due to the inductive relation of the coil 20 to coil 29. The shield 5 is thus given a negative charge which terminates the current flow in the main circuit. Thetermmation of current flow 1n the mam circult a1- -quency desired.

reverse or to cease, whereupon current flow in the main circuit through the tube 1 is reestablished, again causing the induced current flow in coil 20 to'establish a negative charge on the shield 5,- terminating current flow in the main circuit. This cycle may be caused to occur at practically any frequency desired, dependent on the electric characteristics of the various circuits. The interlinkage ofthe main circuit coils and the work circuit coils and the resistance of the work circuit are very important, as well as current-voltage-time-characteristics of the control circuit, in the operation of the de- .lows the current the control circuit to i vice, all of which con'formto electric practice.

The alternating current generated in thecally any frequency and as high as 1,500,000,

or higher frequencies.

In the system shown, the various circuits may be so adjusted that current-normally passes freely through the device 1, but owing to the inductive relation of the coils 16,

20 an d 29, an impulse flow in the'supply circuit induces current in the control circuit,

which current causes a negative charge to the shield adjacent to the positive electrode thereby stopping the flow of current in the main circuit. 11 the stoppage of current flow the current in the control circuit ceases,

whereupon current flow is reestablished in the mam circuit which is again terminated by the current in the control circuit, as above set forth, 1producing currents in the associated wor circuit ofpractically any fre- The operation may be varied by varying the polarity of the current induced in the control circuit, whereupon on current flow in the main circuit the positive current willbe present at the shield 5 near the positive 2, but the control circuit being in inductive relation to an oscillatory circuit, or being itself an oscillatory circuit, on thereturn impulse of the oscillation will have current flow in the gpposite direction, which will cause the shiel at the positive electrode to be negative and terminate the current flow throu h the device. This operation will repeat itse f successively causing variation in the main current flow.

Another operation which may take place is that on initial current flow through the mam circuit-inductance being reversed will cause shield 5 to be positively charged,

but on reversal of the current flow due to either the oscillatory nature of the control circuit to which it is inductively related will cause shield 5 to be charged .negatively and limiting or-aflecting the electrical action at shield 5, and control is here shown by means of inductance coil 28 operatively associated with a mlcrophone circuit '26 or any source of alternating currents indicated convention- For certain purposesthe current flow control by shield 5 is so complete that in cerhtain organizations, .such as that shown in Fig. 3, the shield 7 may be omitted and the device operated by means of electric currents applied to shield 5 alone. These currents may be applied from any source whatsoever independent of interaction ofcoils 20 and 29 and the operation may be performed with devices containing vapors or gases of considerable density as distinguished from high vacuum devices.

While have described the use of the control shield 5, or the shields 5 and 7, as a means of terminating or moderating the main current flow through the device 1' to produce alternating current from said terminations or said moderations, I prefer for most purposes to cause the shields'to'terminate the current flow in the operation of the device, as the heating effects within the device will be less.

While Ihave describedthe device as a controlled self-controlled generator of alternating currents, itwill be-understood that the device is useful as agenerator of alternating currents-controlled from any source.

- I claim as my invention:

1. In the production. of alternating currents from a direct current or varying cur-- rent supply source which consists in passing current from said supply between the main terminals of a conducting device having a.

- sealed container and a vaporizable main negative electrode, applying the current flow 'thus produced to, initiate oscillations in a work circuit and in a control circuit co-operatively related to said supply circuit, and applying the oscillations of the control circuit to cause a charge on the current flowing in said conducting device to terminate said current flow, the step of preventing con centration of the current stream between said main terminals which comprises a plying the charge from said control circuit substantially uniformly across the discharge path between said main electrodes.

rents from a direct current or varying current supply source by means of an electron discharge device having a mam positive electrode, a vaporizable main negative electrode,

and a control electrode, the step of prevent- 2. In the production of alternating cursubstantially uniformly across the discharge path between said main electrodes.

3. In a system of electrical distribution, I

the combination with asource of electric current, of a conducting device having a sealed container and a main positive and a vaporizable main negative, electrode, and a" member extending from wall to wall of the v device therein and transversely of the current path of said device and serving to prevent concentration of the current flow between said main electrodes, a work circuit inductively related to the supply circuit, and means connected with the supply circuit and with the said conducting device for causing the termination of current flow through said device.

4. In a system of electrical distribution, the combination with a source of electric current, of a conducting device having a sealed container and .a main positive and a vaporizable main negative electrode, and a member therein extending across the walls of the device and transversely of the currentpath of said device and serving to prevent conce'ntratidn of the current flow between said main electrodes, a work circuit inductively related to the suppl circuit, and a control circuit inductively related to the supply and work circuits for causing the termination of current flow through said device.

5. In a system of electrical distribution, the metho-d of operation which consists in passing currentfrom a source of supply etween the main terminals of a conducting devicehav-ing a sealed container, a main negrial and through a member therein extending across the walls of the device and transversely of the current path of said device 'ative electrode which is of vaporizable mateand serving to prevent concentration of curvice and serving to prevent concentration of current flowin through it and applying the current flow t us produced to initiate oscillations in a control circuit and applying tra-tion, creating oscillations in a control circuit and applying the oscillations of the control circuit to the current flowing in said conducting device to modify the main current flow therein.

8. In a system of electrical distribution, the combination with a source of electric current, of a conducting device having a sealed container and a, main positive and a vaporizable main ne ative electrode and a member therein exten ing across the Walls of the device and transversely of the cur-.

rent path of said device and serving to prevent concentration of the current flow between said main electrodes and a control circuit in operative relation to the said member impressing a ne ative charge on said member for causing t e termination of current flow through said device.

9. In a system of electrical distribution,

the combination with a source of electric current, of a conducting device havmg a sealed container and a mam positlve and a vaporizable main negative electrode and a member therein extending across the walls of the'device and transversely of the current path of said'device and serving to prevent concentration of the current flow between said main electrodes and a control cir-' cuit in operative relation to th'e'said-member impressing a negative charge on sand member for modifying the current flow through said device.

10. In a system of electrical distribution, the combination with a source of electric current, of a conducting device having a sealed envelope, a main positive electrode and avaporizable main negative electrode, a control electrode between said main electrodes of such size and shape as to present across the discharge ath between said main electrodes at substantially uniform distribution of control electrode body and of open spaces between-parts of said body.

11. In a system of electrical distribution, the combination with a source 0 ie'lectric current, of a conducting device aving a sealed envelope, a main positive electrode and a vaporizable main negative electrode, and means for presenting a negative charge between said main electrodes and for distributing-current flowing betw en said main electrodes uniformly across the path of its flow.

In testimony whereof I heieto afiix my signature. 1

PETER COOPER HEWITT. 

